95 seadoo gts driving me crazy (stalling)

[Bigredram87]

Ok so I have been having a problem with this ski all of last year. The ski starts up pretty good, drive it about a mile in a no wake zone till we get out to lake. It runs kinda smokey for first few minutes which being a 2 stroke I would say normal. Drives fine on lake wot and sometimes stopping to talk to other ski. The problem is everytime I bring this ski back it stalls out after about 5 minutes of idling. I can struggle try and try to get it to start and it may fire up for 5 seconds and than die again. Usually end up towing it back with other ski the last leg. Next time we go out runs fine at beginning and than same thing. I am changing out the fuel lines this weekend just for heck of it(there old gray ones). I can't really tell if it's loading up with fuel when it stalls or what? I have also put it on a small pond and tied it off, let it run at idle for maybe 15 minutes never stalled it's almost like it has something to do with the wot to idle transition(however it is delayed like 5 minutes)I was considering a carb kit also. Please let me know what you guys think

 

[racerxxx]

You're on the right track. First I would do a compression check and post your findings before spending any money. You should have changed the gray fuel lines as soon as you got it, they're the kiss of death. They breakdown and plug up the carb(s) and will rob the engine of the proper amount of gas and lean out thus ruining the engine. Look around the connection points on the carbs, look for green goo. Also at a minimum you will need to tear down the carb(s) and clean them. Then inspect them to see if they need any replacement parts. If it were me, I would just rebuild the carb(s) and put in new needle and seat. Also try and get genuine Mikuini kits for the carb rebuild.

 

[Bigredram87]

Ok great I will do compression check this weekend and post my findings.

 

[racerxxx]

Ok great I will do compression check this weekend and post my findings.

Remember, do it on a cold engine with the throttle wide open--just in case you need to know

 

[Bigredram87]

Ok dumb question i have access to a compression checker but I actually have a leak down tester handy. Can I use the leak down tester on the jetski or should I go get the compression tester? I haven't used a leak down in about 10 years so I'm kind of rusty on why this would or wouldn't work.

 

[RodInEscondido]

Ok dumb question i have access to a compression checker but I actually have a leak down tester handy. Can I use the leak down tester on the jetski or should I go get the compression tester? I haven't used a leak down in about 10 years so I'm kind of rusty on why this would or wouldn't work.

I am no expert, but do not recall seeing any posts here regarding using a leak-down tester on the 2-strokes which means it would be a little difficult to compare readings. The only place I have seen leakdown testers is very extensively with aviation 4-strokes and some times on automotive 4-strokes.

It has been my experience that it is best that you compare the readings from multiple compression testers (almost made very bad decisions based on the reading from one compression tester). Sounds like you have your ski on a trailer or other mobile device so you probably pull up to your local auto parts store (2 of them) and borrow a tester.

If ski has sat for a while it is best to clean out the fuel system and always use fresh gas.

Rod

 

[racerxxx]

Yep, I have never used a leak down on a 2 stroke but have on a few cars and trucks. Compression numbers are easier for us to interpret.

 

[Sportster-2001-951C-Stock]

Leakdown testers are really getting down to professional technical analysis levels, perhaps if your life depended on it it might be a good practice, such as for periodic aircraft airworthiness certification.

It might be interesting to hear of your findings but a straight up compression test will suffice, we're not launching rockets, we're just trying to keep a boat motor running!

 

[Bigredram87]

Ok I think I have figured out the problem So the compression tested Good, Rebuilt the gunked up carb with a new Carb kit and replaced all the fuel lines. After I put everything together I pulled the throttle and noticed something interesting. The oil pump opens up when you give it throttle but it barely returns at all when you let off the throttle!! the cable gets slack and the return spring is so weak it doesnt pull the oil pump back! So that would explain the stalling at idle. I was hoping you guys could please give me a clear answer(I keep reading the forum and haven't came up with a good determination) Can I just take the pump off and remove the pump shaft, Leave all lines connected and leave some oil in reservoir for rotary, pre Mix and be done? THANKS SO MUCH

 

[Sportster-2001-951C-Stock]

Ok I think I have figured out the problem So the compression tested Good, Rebuilt the gunked up carb with a new Carb kit and replaced all the fuel lines. After I put everything together I pulled the throttle and noticed something interesting. The oil pump opens up when you give it throttle but it barely returns at all when you let off the throttle!! the cable gets slack and the return spring is so weak it doesnt pull the oil pump back! So that would explain the stalling at idle. I was hoping you guys could please give me a clear answer(I keep reading the forum and haven't came up with a good determination) Can I just take the pump off and remove the pump shaft, Leave all lines connected and leave some oil in reservoir for rotary, pre Mix and be done? THANKS SO MUCH

Excessive oil supply will definitely cause running problems! Actually, the oil injection system is quite robust and reliable IF it's PROPERLY calibrated and maintained, fortunately this is an easy task. In your case, I suspect the lever arm spring is out of position, is the pump lever spring damaged or does the pump lever just need to be rotated around one turn to catch the spring and create the cable tension? If this is the case, simply disconnect the cable and rotate the lever in the opposite direction of cable pull to tension the spring, then reconnect the cable?

Otherwise as you said, it's necessary to maintain oil inside the rotary valve cavity to lubricate the two gears and bearings while the fuel can be mixed to carry the remainder of the lubricating oil as it moves through the carburetor and through the crankcase normally. Oil consumption will be considerably more, though.

Also, make sure if you decide to keep using the injection (I believe it's worth keeping), to check the condition of the rubber oil lines from the oil pump to the intake manifold, the rubber will deteriorate over time and should be replaced periodically. The inside diameter size is 3/32 and the material is Tygon F-4040-A

 

[Sportster-2001-951C-Stock]

Also I should mention since this may be your first oil injection "party", there are two marks that should be aligned while the throttle is in the idle position. The first of which is on the pump body and the second is on the pump lever, the cable length must be adjusted till these two lines are straight with each other.

If you don't have a copy of the factory service manual for this motor, I suggest you locate one b/c this alignment procedure is in there along with all the other adjustments and service procedures, don't leave home without this manual b/c it's gold, and very helpful! You'll be glad you did!

 

[Bigredram87]

Also I should mention since this may be your first oil injection "party", there are two marks that should be aligned while the throttle is in the idle position. The first of which is on the pump body and the second is on the pump lever, the cable length must be adjusted till these two lines are straight with each other.

If you don't have a copy of the factory service manual for this motor, I suggest you locate one b/c this alignment procedure is in there along with all the other adjustments and service procedures, don't leave home without this manual b/c it's gold, and very helpful! You'll be glad you did!

Great advice !!! The hook of the return spring was just floating and was not wound. I did exactly as you said and I now have a returning oil pump arm. I do have a manual and have to find a mirror to look in there and see if I am aligned thank you so much for the help